The present invention relates generally to the field of heating, ventilation, and air conditioning (HVAC) systems. The present invention relates more particularly to systems and methods for detecting and responding to a disturbance in a HVAC system in the presence of a noisy data signal produced by a measurement device.
HVAC control systems are typically used to monitor and control temperature, humidity, air flow, air quality, and other conditions within a building or building system. HVAC measurement devices (e.g., temperature sensors, pressure sensors, flow sensors, etc.) can produce noisy data signals. Noise in a data signal can hinder the operation of a HVAC controller and may prevent the HVAC system from achieving optimal control. For example, noise in a data signal can delay or prevent a controller from recognizing a real disturbance to the system.
Some HVAC equipment is configured to automatically collect, analyze, and report performance data. One potential problem in HVAC systems is that aging or damaged components (e.g., contactors in a compressor unit) can cause the supply line voltage to decrease or “sag.” If the supply line voltage drops below a minimum necessary value, the HVAC equipment may begin to turn on and off intermittently. This behavior can cause other problems in a HVAC system including equipment damage or inaccurate diagnostic results. Noise in a measured voltage signal can delay or prevent recognition of a disturbance in the supply voltage, providing one example of a challenge caused by noisy measurements.
Various signal processing techniques have been used to reduce or eliminate noise in a measured signal. However, conventional noise reduction techniques are computationally expensive and often produce a signal which “lags” behind the measured values, providing challenges to the process of disturbance detection. In the presence of a noisy measurement signal, it is challenging to detect and respond to disturbances in a HVAC system.